Photographs can indeed be engraved into crystal. This is done using laser technology on 2D and 3D crystal platforms. Because crystal is transparent, the laser can penetrate through it without damaging the material to have the picture engraved into the piece of crystal.
Many retailers, such as 3DLaserGifts.com, Things Remembered and CrystalPrints.com, offer crystal-engraved items and crystal engraving services online. The photo-engraved crystal items on these sites range from about $39 to $400, as of March 2015. They come in a variety of shapes and sizes, such as bottle stoppers. They can also be further personalized with words and graphic designs.